Destroy doesn't destroy - ruby-on-rails

Question

I've 3 models user formation & achat(let's translate to a sort of billing).
A user cand buy a formation, it will create an achat. For reasons I need to delete one achat. But I didn't succeed. I tried the following work-flow to check my code:
irb(main):048:0> u.achats.length
=> 1
irb(main):049:0> u.achats.first.destroy!
(0.1ms) BEGIN
(0.1ms) COMMIT
=> #<Achat id: 8, formation_id: 14, created_at: "2015-06-29 16:08:39", nom_formation: "foo", prix: 0.0, quantite: 1, chapitre_id: nil, user_id: 10, taux_commission: 35, updated_at: "2015-06-29 16:08:39", numero_facture: nil, bon_reduction_id: nil>
irb(main):050:0> u.achats.length
=> 1
So it isn't deleted from the database. How should I destroy the achat?
Here are a (simpler) version of my models:
# coding: utf-8
class User < ActiveRecord::Base
rolify :role_cname => 'Role'
# Include default devise modules. Others available are:
# :confirmable, :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
#Tous les achats de cette utilisateur
has_many :achats
#Toutes les formations achetés par cet utilisateur
has_many :formations, :through => :achats
end
#Classe liant une formation à un utilisateur
class Achat < ActiveRecord::Base
#Lien vers l'utilisateur qui a acheté cette formation
belongs_to :user
#Appartient à la classe Formation
belongs_to :formation
end
#Classe récupérant les différentes informations liées à toutes les formations présentes pour le site
class Formation < ActiveRecord::Base
#Auteur de cette formation
belongs_to :user
# Gestion de la relation pour l'achat
has_many :achats
#Si la formation est publique alors on ne fait que changer le statut et la date de suppression
#Si la formation n'a jamais été publié, alors on la supprime totalement de la base
def destroy
#Si la formation est déja supprimée on bloque la chose
if(self.status.id == 3)
return FORMATION_DEJA_SUPPRIME
else
update_attribute(:status, Status.find(2))
end
end
# Gestion de la suppression d'un produit
def delete!
update_attribute(:dateSuppression, Time.now)
end
end
I've been through this question: dependent: :destroy doesn't work (has_many association) but it didn't helped...

Answer 1

Record variable still available even destroyed. Try
Achat.find(8) # or some another destroyed id
to make sure you have deleted the record from the database
P.S. Consider destroyed? method of rails for understanding

Answer 2

As #josh-burgess also pointed out, you could destroy and then reload the object.
u.achats.first.destroy!
u.achats.reload